git.oblomov.eu Git - linux-2.6/blob - drivers/usb/serial/oti6858.c

   1 /*
   2  * Ours Technology Inc. OTi-6858 USB to serial adapter driver.
   3  *
   4  * Copyleft  (C) 2007 Kees Lemmens (adapted for kernel 2.6.20)
   5  * Copyright (C) 2006 Tomasz Michal Lukaszewski (FIXME: add e-mail)
   6  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
   7  * Copyright (C) 2003 IBM Corp.
   8  *
   9  * Many thanks to the authors of pl2303 driver: all functions in this file
  10  * are heavily based on pl2303 code, buffering code is a 1-to-1 copy.
  11  *
  12  * Warning! You use this driver on your own risk! The only official
  13  * description of this device I have is datasheet from manufacturer,
  14  * and it doesn't contain almost any information needed to write a driver.
  15  * Almost all knowlegde used while writing this driver was gathered by:
  16  *  - analyzing traffic between device and the M$ Windows 2000 driver,
  17  *  - trying different bit combinations and checking pin states
  18  *    with a voltmeter,
  19  *  - receiving malformed frames and producing buffer overflows
  20  *    to learn how errors are reported,
  21  * So, THIS CODE CAN DESTROY OTi-6858 AND ANY OTHER DEVICES, THAT ARE
  22  * CONNECTED TO IT!
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2 of the License.
  27  *
  28  * See Documentation/usb/usb-serial.txt for more information on using this driver
  29  *
  30  * TODO:
  31  *  - implement correct flushing for ioctls and oti6858_close()
  32  *  - check how errors (rx overflow, parity error, framing error) are reported
  33  *  - implement oti6858_break_ctl()
  34  *  - implement more ioctls
  35  *  - test/implement flow control
  36  *  - allow setting custom baud rates
  37  */
  38
  39 #include <linux/kernel.h>
  40 #include <linux/errno.h>
  41 #include <linux/init.h>
  42 #include <linux/slab.h>
  43 #include <linux/tty.h>
  44 #include <linux/tty_driver.h>
  45 #include <linux/tty_flip.h>
  46 #include <linux/serial.h>
  47 #include <linux/module.h>
  48 #include <linux/moduleparam.h>
  49 #include <linux/spinlock.h>
  50 #include <linux/usb.h>
  51 #include <linux/usb/serial.h>
  52 #include <asm/uaccess.h>
  53 #include "oti6858.h"
  54
  55 #define OTI6858_DESCRIPTION \
  56         "Ours Technology Inc. OTi-6858 USB to serial adapter driver"
  57 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
  58 #define OTI6858_VERSION "0.1"
  59
  60 static struct usb_device_id id_table [] = {
  61         { USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
  62         { }
  63 };
  64
  65 MODULE_DEVICE_TABLE(usb, id_table);
  66
  67 static struct usb_driver oti6858_driver = {
  68         .name =         "oti6858",
  69         .probe =        usb_serial_probe,
  70         .disconnect =   usb_serial_disconnect,
  71         .id_table =     id_table,
  72         .no_dynamic_id =        1,
  73 };
  74
  75 static int debug;
  76
  77
  78 /* buffering code, copied from pl2303 driver */
  79 #define PL2303_BUF_SIZE         1024
  80 #define PL2303_TMP_BUF_SIZE     1024
  81
  82 struct oti6858_buf {
  83         unsigned int    buf_size;
  84         char            *buf_buf;
  85         char            *buf_get;
  86         char            *buf_put;
  87 };
  88
  89 /* requests */
  90 #define OTI6858_REQ_GET_STATUS          (USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
  91 #define OTI6858_REQ_T_GET_STATUS        0x01
  92
  93 #define OTI6858_REQ_SET_LINE            (USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
  94 #define OTI6858_REQ_T_SET_LINE          0x00
  95
  96 #define OTI6858_REQ_CHECK_TXBUFF        (USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
  97 #define OTI6858_REQ_T_CHECK_TXBUFF      0x00
  98
  99 /* format of the control packet */
 100 struct oti6858_control_pkt {
 101         u16     divisor;        /* baud rate = 96000000 / (16 * divisor), LE */
 102 #define OTI6858_MAX_BAUD_RATE   3000000
 103         u8      frame_fmt;
 104 #define FMT_STOP_BITS_MASK      0xc0
 105 #define FMT_STOP_BITS_1         0x00
 106 #define FMT_STOP_BITS_2         0x40    /* 1.5 stop bits if FMT_DATA_BITS_5 */
 107 #define FMT_PARITY_MASK         0x38
 108 #define FMT_PARITY_NONE         0x00
 109 #define FMT_PARITY_ODD          0x08
 110 #define FMT_PARITY_EVEN         0x18
 111 #define FMT_PARITY_MARK         0x28
 112 #define FMT_PARITY_SPACE        0x38
 113 #define FMT_DATA_BITS_MASK      0x03
 114 #define FMT_DATA_BITS_5         0x00
 115 #define FMT_DATA_BITS_6         0x01
 116 #define FMT_DATA_BITS_7         0x02
 117 #define FMT_DATA_BITS_8         0x03
 118         u8      something;      /* always equals 0x43 */
 119         u8      control;        /* settings of flow control lines */
 120 #define CONTROL_MASK            0x0c
 121 #define CONTROL_DTR_HIGH        0x08
 122 #define CONTROL_RTS_HIGH        0x04
 123         u8      tx_status;
 124 #define TX_BUFFER_EMPTIED       0x09
 125         u8      pin_state;
 126 #define PIN_MASK                0x3f
 127 #define PIN_RTS                 0x20    /* output pin */
 128 #define PIN_CTS                 0x10    /* input pin, active low */
 129 #define PIN_DSR                 0x08    /* input pin, active low */
 130 #define PIN_DTR                 0x04    /* output pin */
 131 #define PIN_RI                  0x02    /* input pin, active low */
 132 #define PIN_DCD                 0x01    /* input pin, active low */
 133         u8      rx_bytes_avail;         /* number of bytes in rx buffer */;
 134 };
 135
 136 #define OTI6858_CTRL_PKT_SIZE   sizeof(struct oti6858_control_pkt)
 137 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
 138         (    ((a)->divisor == (priv)->pending_setup.divisor) \
 139           && ((a)->control == (priv)->pending_setup.control) \
 140           && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt) )
 141
 142 /* function prototypes */
 143 static int oti6858_open(struct usb_serial_port *port, struct file *filp);
 144 static void oti6858_close(struct usb_serial_port *port, struct file *filp);
 145 static void oti6858_set_termios(struct usb_serial_port *port,
 146                                 struct ktermios *old);
 147 static int oti6858_ioctl(struct usb_serial_port *port, struct file *file,
 148                         unsigned int cmd, unsigned long arg);
 149 static void oti6858_read_int_callback(struct urb *urb);
 150 static void oti6858_read_bulk_callback(struct urb *urb);
 151 static void oti6858_write_bulk_callback(struct urb *urb);
 152 static int oti6858_write(struct usb_serial_port *port,
 153                         const unsigned char *buf, int count);
 154 static int oti6858_write_room(struct usb_serial_port *port);
 155 static void oti6858_break_ctl(struct usb_serial_port *port, int break_state);
 156 static int oti6858_chars_in_buffer(struct usb_serial_port *port);
 157 static int oti6858_tiocmget(struct usb_serial_port *port, struct file *file);
 158 static int oti6858_tiocmset(struct usb_serial_port *port, struct file *file,
 159                                 unsigned int set, unsigned int clear);
 160 static int oti6858_startup(struct usb_serial *serial);
 161 static void oti6858_shutdown(struct usb_serial *serial);
 162
 163 /* functions operating on buffers */
 164 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size);
 165 static void oti6858_buf_free(struct oti6858_buf *pb);
 166 static void oti6858_buf_clear(struct oti6858_buf *pb);
 167 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb);
 168 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb);
 169 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
 170                                         unsigned int count);
 171 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
 172                                         unsigned int count);
 173
 174
 175 /* device info */
 176 static struct usb_serial_driver oti6858_device = {
 177         .driver = {
 178                 .owner =        THIS_MODULE,
 179                 .name =         "oti6858",
 180         },
 181         .id_table =             id_table,
 182         .num_interrupt_in =     1,
 183         .num_bulk_in =          1,
 184         .num_bulk_out =         1,
 185         .num_ports =            1,
 186         .open =                 oti6858_open,
 187         .close =                oti6858_close,
 188         .write =                oti6858_write,
 189         .ioctl =                oti6858_ioctl,
 190         .break_ctl =            oti6858_break_ctl,
 191         .set_termios =          oti6858_set_termios,
 192         .tiocmget =             oti6858_tiocmget,
 193         .tiocmset =             oti6858_tiocmset,
 194         .read_bulk_callback =   oti6858_read_bulk_callback,
 195         .read_int_callback =    oti6858_read_int_callback,
 196         .write_bulk_callback =  oti6858_write_bulk_callback,
 197         .write_room =           oti6858_write_room,
 198         .chars_in_buffer =      oti6858_chars_in_buffer,
 199         .attach =               oti6858_startup,
 200         .shutdown =             oti6858_shutdown,
 201 };
 202
 203 struct oti6858_private {
 204         spinlock_t lock;
 205
 206         struct oti6858_buf *buf;
 207         struct oti6858_control_pkt status;
 208
 209         struct {
 210                 u8 read_urb_in_use;
 211                 u8 write_urb_in_use;
 212                 u8 termios_initialized;
 213         } flags;
 214         struct delayed_work delayed_write_work;
 215
 216         struct {
 217                 u16 divisor;
 218                 u8 frame_fmt;
 219                 u8 control;
 220         } pending_setup;
 221         u8 transient;
 222         u8 setup_done;
 223         struct delayed_work delayed_setup_work;
 224
 225         wait_queue_head_t intr_wait;
 226         struct usb_serial_port *port;   /* USB port with which associated */
 227 };
 228
 229 #undef dbg
 230 /* #define dbg(format, arg...) printk(KERN_INFO "%s: " format "\n", __FILE__, ## arg) */
 231 #define dbg(format, arg...) printk(KERN_INFO "" format "\n", ## arg)
 232
 233 static void setup_line(struct work_struct *work)
 234 {
 235         struct oti6858_private *priv = container_of(work, struct oti6858_private, delayed_setup_work.work);
 236         struct usb_serial_port *port = priv->port;
 237         struct oti6858_control_pkt *new_setup;
 238         unsigned long flags;
 239         int result;
 240
 241         dbg("%s(port = %d)", __FUNCTION__, port->number);
 242
 243         if ((new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL)) == NULL) {
 244                 dev_err(&port->dev, "%s(): out of memory!\n", __FUNCTION__);
 245                 /* we will try again */
 246                 schedule_delayed_work(&priv->delayed_setup_work, msecs_to_jiffies(2));
 247                 return;
 248         }
 249
 250         result = usb_control_msg(port->serial->dev,
 251                                 usb_rcvctrlpipe(port->serial->dev, 0),
 252                                 OTI6858_REQ_T_GET_STATUS,
 253                                 OTI6858_REQ_GET_STATUS,
 254                                 0, 0,
 255                                 new_setup, OTI6858_CTRL_PKT_SIZE,
 256                                 100);
 257
 258         if (result != OTI6858_CTRL_PKT_SIZE) {
 259                 dev_err(&port->dev, "%s(): error reading status\n", __FUNCTION__);
 260                 kfree(new_setup);
 261                 /* we will try again */
 262                 schedule_delayed_work(&priv->delayed_setup_work, msecs_to_jiffies(2));
 263                 return;
 264         }
 265
 266         spin_lock_irqsave(&priv->lock, flags);
 267         if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
 268                 new_setup->divisor = priv->pending_setup.divisor;
 269                 new_setup->control = priv->pending_setup.control;
 270                 new_setup->frame_fmt = priv->pending_setup.frame_fmt;
 271
 272                 spin_unlock_irqrestore(&priv->lock, flags);
 273                 result = usb_control_msg(port->serial->dev,
 274                                         usb_sndctrlpipe(port->serial->dev, 0),
 275                                         OTI6858_REQ_T_SET_LINE,
 276                                         OTI6858_REQ_SET_LINE,
 277                                         0, 0,
 278                                         new_setup, OTI6858_CTRL_PKT_SIZE,
 279                                         100);
 280         } else {
 281                 spin_unlock_irqrestore(&priv->lock, flags);
 282                 result = 0;
 283         }
 284         kfree(new_setup);
 285
 286         spin_lock_irqsave(&priv->lock, flags);
 287         if (result != OTI6858_CTRL_PKT_SIZE)
 288                 priv->transient = 0;
 289         priv->setup_done = 1;
 290         spin_unlock_irqrestore(&priv->lock, flags);
 291
 292         dbg("%s(): submitting interrupt urb", __FUNCTION__);
 293         port->interrupt_in_urb->dev = port->serial->dev;
 294         result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
 295         if (result != 0) {
 296                 dev_err(&port->dev, "%s(): usb_submit_urb() failed"
 297                                 " with error %d\n", __FUNCTION__, result);
 298         }
 299 }
 300
 301 void send_data(struct work_struct *work)
 302 {
 303         struct oti6858_private *priv = container_of(work, struct oti6858_private, delayed_write_work.work);
 304         struct usb_serial_port *port = priv->port;
 305         int count = 0, result;
 306         unsigned long flags;
 307         unsigned char allow;
 308
 309         dbg("%s(port = %d)", __FUNCTION__, port->number);
 310
 311         spin_lock_irqsave(&priv->lock, flags);
 312         if (priv->flags.write_urb_in_use) {
 313                 spin_unlock_irqrestore(&priv->lock, flags);
 314                 schedule_delayed_work(&priv->delayed_write_work, msecs_to_jiffies(2));
 315                 return;
 316         }
 317         priv->flags.write_urb_in_use = 1;
 318
 319         count = oti6858_buf_data_avail(priv->buf);
 320         spin_unlock_irqrestore(&priv->lock, flags);
 321         if (count > port->bulk_out_size)
 322                 count = port->bulk_out_size;
 323
 324         if (count != 0) {
 325                 result = usb_control_msg(port->serial->dev,
 326                                 usb_rcvctrlpipe(port->serial->dev, 0),
 327                                 OTI6858_REQ_T_CHECK_TXBUFF,
 328                                 OTI6858_REQ_CHECK_TXBUFF,
 329                                 count, 0, &allow, 1, 100);
 330                 if (result != 1 || allow != 0)
 331                         count = 0;
 332         }
 333
 334         if (count == 0) {
 335                 priv->flags.write_urb_in_use = 0;
 336
 337                 dbg("%s(): submitting interrupt urb", __FUNCTION__);
 338                 port->interrupt_in_urb->dev = port->serial->dev;
 339                 result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
 340                 if (result != 0) {
 341                         dev_err(&port->dev, "%s(): usb_submit_urb() failed"
 342                                 " with error %d\n", __FUNCTION__, result);
 343                 }
 344                 return;
 345         }
 346
 347         spin_lock_irqsave(&priv->lock, flags);
 348         oti6858_buf_get(priv->buf, port->write_urb->transfer_buffer, count);
 349         spin_unlock_irqrestore(&priv->lock, flags);
 350
 351         port->write_urb->transfer_buffer_length = count;
 352         port->write_urb->dev = port->serial->dev;
 353         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 354         if (result != 0) {
 355                 dev_err(&port->dev, "%s(): usb_submit_urb() failed"
 356                                " with error %d\n", __FUNCTION__, result);
 357                 priv->flags.write_urb_in_use = 0;
 358         }
 359
 360         usb_serial_port_softint(port);
 361 }
 362
 363 static int oti6858_startup(struct usb_serial *serial)
 364 {
 365         struct usb_serial_port *port = serial->port[0];
 366         struct oti6858_private *priv;
 367         int i;
 368
 369         for (i = 0; i < serial->num_ports; ++i) {
 370                 priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
 371                 if (!priv)
 372                         break;
 373                 priv->buf = oti6858_buf_alloc(PL2303_BUF_SIZE);
 374                 if (priv->buf == NULL) {
 375                         kfree(priv);
 376                         break;
 377                 }
 378
 379                 spin_lock_init(&priv->lock);
 380                 init_waitqueue_head(&priv->intr_wait);
 381 //              INIT_WORK(&priv->setup_work, setup_line, serial->port[i]);
 382 //              INIT_WORK(&priv->write_work, send_data, serial->port[i]);
 383                 priv->port = port;
 384                 INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
 385                 INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
 386
 387                 usb_set_serial_port_data(serial->port[i], priv);
 388         }
 389         if (i == serial->num_ports)
 390                 return 0;
 391
 392         for (--i; i >= 0; --i) {
 393                 priv = usb_get_serial_port_data(serial->port[i]);
 394                 oti6858_buf_free(priv->buf);
 395                 kfree(priv);
 396                 usb_set_serial_port_data(serial->port[i], NULL);
 397         }
 398         return -ENOMEM;
 399 }
 400
 401 static int oti6858_write(struct usb_serial_port *port,
 402                         const unsigned char *buf, int count)
 403 {
 404         struct oti6858_private *priv = usb_get_serial_port_data(port);
 405         unsigned long flags;
 406
 407         dbg("%s(port = %d, count = %d)", __FUNCTION__, port->number, count);
 408
 409         if (!count)
 410                 return count;
 411
 412         spin_lock_irqsave(&priv->lock, flags);
 413         count = oti6858_buf_put(priv->buf, buf, count);
 414         spin_unlock_irqrestore(&priv->lock, flags);
 415
 416         return count;
 417 }
 418
 419 static int oti6858_write_room(struct usb_serial_port *port)
 420 {
 421         struct oti6858_private *priv = usb_get_serial_port_data(port);
 422         int room = 0;
 423         unsigned long flags;
 424
 425         dbg("%s(port = %d)", __FUNCTION__, port->number);
 426
 427         spin_lock_irqsave(&priv->lock, flags);
 428         room = oti6858_buf_space_avail(priv->buf);
 429         spin_unlock_irqrestore(&priv->lock, flags);
 430
 431         return room;
 432 }
 433
 434 static int oti6858_chars_in_buffer(struct usb_serial_port *port)
 435 {
 436         struct oti6858_private *priv = usb_get_serial_port_data(port);
 437         int chars = 0;
 438         unsigned long flags;
 439
 440         dbg("%s(port = %d)", __FUNCTION__, port->number);
 441
 442         spin_lock_irqsave(&priv->lock, flags);
 443         chars = oti6858_buf_data_avail(priv->buf);
 444         spin_unlock_irqrestore(&priv->lock, flags);
 445
 446         return chars;
 447 }
 448
 449 static void oti6858_set_termios(struct usb_serial_port *port,
 450                                 struct ktermios *old_termios)
 451 {
 452         struct oti6858_private *priv = usb_get_serial_port_data(port);
 453         unsigned long flags;
 454         unsigned int cflag;
 455         u8 frame_fmt, control;
 456         u16 divisor;
 457         int br;
 458
 459         dbg("%s(port = %d)", __FUNCTION__, port->number);
 460
 461         if (!port->tty || !port->tty->termios) {
 462                 dbg("%s(): no tty structures", __FUNCTION__);
 463                 return;
 464         }
 465
 466         spin_lock_irqsave(&priv->lock, flags);
 467         if (!priv->flags.termios_initialized) {
 468                 *(port->tty->termios) = tty_std_termios;
 469                 port->tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
 470                 priv->flags.termios_initialized = 1;
 471                 port->tty->termios->c_ispeed = 38400;
 472                 port->tty->termios->c_ospeed = 38400;
 473         }
 474         spin_unlock_irqrestore(&priv->lock, flags);
 475
 476         cflag = port->tty->termios->c_cflag;
 477
 478         spin_lock_irqsave(&priv->lock, flags);
 479         divisor = priv->pending_setup.divisor;
 480         frame_fmt = priv->pending_setup.frame_fmt;
 481         control = priv->pending_setup.control;
 482         spin_unlock_irqrestore(&priv->lock, flags);
 483
 484         frame_fmt &= ~FMT_DATA_BITS_MASK;
 485         switch (cflag & CSIZE) {
 486                 case CS5:
 487                         frame_fmt |= FMT_DATA_BITS_5;
 488                         break;
 489                 case CS6:
 490                         frame_fmt |= FMT_DATA_BITS_6;
 491                         break;
 492                 case CS7:
 493                         frame_fmt |= FMT_DATA_BITS_7;
 494                         break;
 495                 default:
 496                 case CS8:
 497                         frame_fmt |= FMT_DATA_BITS_8;
 498                         break;
 499         }
 500
 501         /* manufacturer claims that this device can work with baud rates
 502          * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
 503          * guarantee that any other baud rate will work (especially
 504          * the higher ones)
 505          */
 506         br = tty_get_baud_rate(port->tty);
 507         if (br == 0) {
 508                 divisor = 0;
 509         } else {
 510                 int real_br;
 511                 br = min(br, OTI6858_MAX_BAUD_RATE);
 512
 513                 divisor = (96000000 + 8 * br) / (16 * br);
 514                 real_br = 96000000 / (16 * divisor);
 515                 divisor = cpu_to_le16(divisor);
 516                 tty_encode_baud_rate(port->tty, real_br, real_br);
 517         }
 518
 519         frame_fmt &= ~FMT_STOP_BITS_MASK;
 520         if ((cflag & CSTOPB) != 0) {
 521                 frame_fmt |= FMT_STOP_BITS_2;
 522         } else {
 523                 frame_fmt |= FMT_STOP_BITS_1;
 524         }
 525
 526         frame_fmt &= ~FMT_PARITY_MASK;
 527         if ((cflag & PARENB) != 0) {
 528                 if ((cflag & PARODD) != 0) {
 529                         frame_fmt |= FMT_PARITY_ODD;
 530                 } else {
 531                         frame_fmt |= FMT_PARITY_EVEN;
 532                 }
 533         } else {
 534                 frame_fmt |= FMT_PARITY_NONE;
 535         }
 536
 537         control &= ~CONTROL_MASK;
 538         if ((cflag & CRTSCTS) != 0)
 539                 control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
 540
 541         /* change control lines if we are switching to or from B0 */
 542         /* FIXME:
 543         spin_lock_irqsave(&priv->lock, flags);
 544         control = priv->line_control;
 545         if ((cflag & CBAUD) == B0)
 546                 priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
 547         else
 548                 priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
 549         if (control != priv->line_control) {
 550                 control = priv->line_control;
 551                 spin_unlock_irqrestore(&priv->lock, flags);
 552                 set_control_lines(serial->dev, control);
 553         } else {
 554                 spin_unlock_irqrestore(&priv->lock, flags);
 555         }
 556         */
 557
 558         spin_lock_irqsave(&priv->lock, flags);
 559         if (divisor != priv->pending_setup.divisor
 560                         || control != priv->pending_setup.control
 561                         || frame_fmt != priv->pending_setup.frame_fmt) {
 562                 priv->pending_setup.divisor = divisor;
 563                 priv->pending_setup.control = control;
 564                 priv->pending_setup.frame_fmt = frame_fmt;
 565         }
 566         spin_unlock_irqrestore(&priv->lock, flags);
 567 }
 568
 569 static int oti6858_open(struct usb_serial_port *port, struct file *filp)
 570 {
 571         struct oti6858_private *priv = usb_get_serial_port_data(port);
 572         struct ktermios tmp_termios;
 573         struct usb_serial *serial = port->serial;
 574         struct oti6858_control_pkt *buf;
 575         unsigned long flags;
 576         int result;
 577
 578         dbg("%s(port = %d)", __FUNCTION__, port->number);
 579
 580         usb_clear_halt(serial->dev, port->write_urb->pipe);
 581         usb_clear_halt(serial->dev, port->read_urb->pipe);
 582
 583         if (port->open_count != 1)
 584                 return 0;
 585
 586         if ((buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL)) == NULL) {
 587                 dev_err(&port->dev, "%s(): out of memory!\n", __FUNCTION__);
 588                 return -ENOMEM;
 589         }
 590
 591         result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
 592                                 OTI6858_REQ_T_GET_STATUS,
 593                                 OTI6858_REQ_GET_STATUS,
 594                                 0, 0,
 595                                 buf, OTI6858_CTRL_PKT_SIZE,
 596                                 100);
 597         if (result != OTI6858_CTRL_PKT_SIZE) {
 598                 /* assume default (after power-on reset) values */
 599                 buf->divisor = cpu_to_le16(0x009c);     /* 38400 bps */
 600                 buf->frame_fmt = 0x03;  /* 8N1 */
 601                 buf->something = 0x43;
 602                 buf->control = 0x4c;    /* DTR, RTS */
 603                 buf->tx_status = 0x00;
 604                 buf->pin_state = 0x5b;  /* RTS, CTS, DSR, DTR, RI, DCD */
 605                 buf->rx_bytes_avail = 0x00;
 606         }
 607
 608         spin_lock_irqsave(&priv->lock, flags);
 609         memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
 610         priv->pending_setup.divisor = buf->divisor;
 611         priv->pending_setup.frame_fmt = buf->frame_fmt;
 612         priv->pending_setup.control = buf->control;
 613         spin_unlock_irqrestore(&priv->lock, flags);
 614         kfree(buf);
 615
 616         dbg("%s(): submitting interrupt urb", __FUNCTION__);
 617         port->interrupt_in_urb->dev = serial->dev;
 618         result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 619         if (result != 0) {
 620                 dev_err(&port->dev, "%s(): usb_submit_urb() failed"
 621                                " with error %d\n", __FUNCTION__, result);
 622                 oti6858_close(port, NULL);
 623                 return -EPROTO;
 624         }
 625
 626         /* setup termios */
 627         if (port->tty)
 628                 oti6858_set_termios(port, &tmp_termios);
 629
 630         return 0;
 631 }
 632
 633 static void oti6858_close(struct usb_serial_port *port, struct file *filp)
 634 {
 635         struct oti6858_private *priv = usb_get_serial_port_data(port);
 636         unsigned long flags;
 637         long timeout;
 638         wait_queue_t wait;
 639
 640         dbg("%s(port = %d)", __FUNCTION__, port->number);
 641
 642         /* wait for data to drain from the buffer */
 643         spin_lock_irqsave(&priv->lock, flags);
 644         timeout = 30 * HZ;      /* PL2303_CLOSING_WAIT */
 645         init_waitqueue_entry(&wait, current);
 646         add_wait_queue(&port->tty->write_wait, &wait);
 647         dbg("%s(): entering wait loop", __FUNCTION__);
 648         for (;;) {
 649                 set_current_state(TASK_INTERRUPTIBLE);
 650                 if (oti6858_buf_data_avail(priv->buf) == 0
 651                 || timeout == 0 || signal_pending(current)
 652                 || port->serial->disconnected)
 653                         break;
 654                 spin_unlock_irqrestore(&priv->lock, flags);
 655                 timeout = schedule_timeout(timeout);
 656                 spin_lock_irqsave(&priv->lock, flags);
 657         }
 658         set_current_state(TASK_RUNNING);
 659         remove_wait_queue(&port->tty->write_wait, &wait);
 660         dbg("%s(): after wait loop", __FUNCTION__);
 661
 662         /* clear out any remaining data in the buffer */
 663         oti6858_buf_clear(priv->buf);
 664         spin_unlock_irqrestore(&priv->lock, flags);
 665
 666         /* wait for characters to drain from the device */
 667         /* (this is long enough for the entire 256 byte */
 668         /* pl2303 hardware buffer to drain with no flow */
 669         /* control for data rates of 1200 bps or more, */
 670         /* for lower rates we should really know how much */
 671         /* data is in the buffer to compute a delay */
 672         /* that is not unnecessarily long) */
 673         /* FIXME
 674         bps = tty_get_baud_rate(port->tty);
 675         if (bps > 1200)
 676                 timeout = max((HZ*2560)/bps,HZ/10);
 677         else
 678         */
 679                 timeout = 2*HZ;
 680         schedule_timeout_interruptible(timeout);
 681         dbg("%s(): after schedule_timeout_interruptible()", __FUNCTION__);
 682
 683         /* cancel scheduled setup */
 684         cancel_delayed_work(&priv->delayed_setup_work);
 685         cancel_delayed_work(&priv->delayed_write_work);
 686         flush_scheduled_work();
 687
 688         /* shutdown our urbs */
 689         dbg("%s(): shutting down urbs", __FUNCTION__);
 690         usb_kill_urb(port->write_urb);
 691         usb_kill_urb(port->read_urb);
 692         usb_kill_urb(port->interrupt_in_urb);
 693
 694         /*
 695         if (port->tty && (port->tty->termios->c_cflag) & HUPCL) {
 696                 // drop DTR and RTS
 697                 spin_lock_irqsave(&priv->lock, flags);
 698                 priv->pending_setup.control &= ~CONTROL_MASK;
 699                 spin_unlock_irqrestore(&priv->lock, flags);
 700         }
 701         */
 702 }
 703
 704 static int oti6858_tiocmset(struct usb_serial_port *port, struct file *file,
 705                                 unsigned int set, unsigned int clear)
 706 {
 707         struct oti6858_private *priv = usb_get_serial_port_data(port);
 708         unsigned long flags;
 709         u8 control;
 710
 711         dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
 712                                 __FUNCTION__, port->number, set, clear);
 713
 714         if (!usb_get_intfdata(port->serial->interface))
 715                 return -ENODEV;
 716
 717         /* FIXME: check if this is correct (active high/low) */
 718         spin_lock_irqsave(&priv->lock, flags);
 719         control = priv->pending_setup.control;
 720         if ((set & TIOCM_RTS) != 0)
 721                 control |= CONTROL_RTS_HIGH;
 722         if ((set & TIOCM_DTR) != 0)
 723                 control |= CONTROL_DTR_HIGH;
 724         if ((clear & TIOCM_RTS) != 0)
 725                 control &= ~CONTROL_RTS_HIGH;
 726         if ((clear & TIOCM_DTR) != 0)
 727                 control &= ~CONTROL_DTR_HIGH;
 728
 729         if (control != priv->pending_setup.control) {
 730                 priv->pending_setup.control = control;
 731         }
 732         spin_unlock_irqrestore(&priv->lock, flags);
 733
 734         return 0;
 735 }
 736
 737 static int oti6858_tiocmget(struct usb_serial_port *port, struct file *file)
 738 {
 739         struct oti6858_private *priv = usb_get_serial_port_data(port);
 740         unsigned long flags;
 741         unsigned pin_state;
 742         unsigned result = 0;
 743
 744         dbg("%s(port = %d)", __FUNCTION__, port->number);
 745
 746         if (!usb_get_intfdata(port->serial->interface))
 747                 return -ENODEV;
 748
 749         spin_lock_irqsave(&priv->lock, flags);
 750         pin_state = priv->status.pin_state & PIN_MASK;
 751         spin_unlock_irqrestore(&priv->lock, flags);
 752
 753         /* FIXME: check if this is correct (active high/low) */
 754         if ((pin_state & PIN_RTS) != 0)
 755                 result |= TIOCM_RTS;
 756         if ((pin_state & PIN_CTS) != 0)
 757                 result |= TIOCM_CTS;
 758         if ((pin_state & PIN_DSR) != 0)
 759                 result |= TIOCM_DSR;
 760         if ((pin_state & PIN_DTR) != 0)
 761                 result |= TIOCM_DTR;
 762         if ((pin_state & PIN_RI) != 0)
 763                 result |= TIOCM_RI;
 764         if ((pin_state & PIN_DCD) != 0)
 765                 result |= TIOCM_CD;
 766
 767         dbg("%s() = 0x%08x", __FUNCTION__, result);
 768
 769         return result;
 770 }
 771
 772 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 773 {
 774         struct oti6858_private *priv = usb_get_serial_port_data(port);
 775         unsigned long flags;
 776         unsigned int prev, status;
 777         unsigned int changed;
 778
 779         spin_lock_irqsave(&priv->lock, flags);
 780         prev = priv->status.pin_state;
 781         spin_unlock_irqrestore(&priv->lock, flags);
 782
 783         while (1) {
 784                 wait_event_interruptible(priv->intr_wait, priv->status.pin_state != prev);
 785                 if (signal_pending(current))
 786                         return -ERESTARTSYS;
 787
 788                 spin_lock_irqsave(&priv->lock, flags);
 789                 status = priv->status.pin_state & PIN_MASK;
 790                 spin_unlock_irqrestore(&priv->lock, flags);
 791
 792                 changed = prev ^ status;
 793                 /* FIXME: check if this is correct (active high/low) */
 794                 if (    ((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
 795                         ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
 796                         ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
 797                         ((arg & TIOCM_CTS) && (changed & PIN_CTS))) {
 798                                 return 0;
 799                 }
 800                 prev = status;
 801         }
 802
 803         /* NOTREACHED */
 804         return 0;
 805 }
 806
 807 static int oti6858_ioctl(struct usb_serial_port *port, struct file *file,
 808                         unsigned int cmd, unsigned long arg)
 809 {
 810         void __user *user_arg = (void __user *) arg;
 811         unsigned int x;
 812
 813         dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
 814                                 __FUNCTION__, port->number, cmd, arg);
 815
 816         switch (cmd) {
 817                 case TCFLSH:
 818                         /* FIXME */
 819                         return 0;
 820
 821                 case TIOCMBIS:
 822                         if (copy_from_user(&x, user_arg, sizeof(x)))
 823                                 return -EFAULT;
 824                         return oti6858_tiocmset(port, NULL, x, 0);
 825
 826                 case TIOCMBIC:
 827                         if (copy_from_user(&x, user_arg, sizeof(x)))
 828                                 return -EFAULT;
 829                         return oti6858_tiocmset(port, NULL, 0, x);
 830
 831                 case TIOCMIWAIT:
 832                         dbg("%s(): TIOCMIWAIT", __FUNCTION__);
 833                         return wait_modem_info(port, arg);
 834
 835                 default:
 836                         dbg("%s(): 0x%04x not supported", __FUNCTION__, cmd);
 837                         break;
 838         }
 839
 840         return -ENOIOCTLCMD;
 841 }
 842
 843 static void oti6858_break_ctl(struct usb_serial_port *port, int break_state)
 844 {
 845         int state;
 846
 847         dbg("%s(port = %d)", __FUNCTION__, port->number);
 848
 849         state = (break_state == 0) ? 0 : 1;
 850         dbg("%s(): turning break %s", __FUNCTION__, state ? "on" : "off");
 851
 852         /* FIXME */
 853 /*
 854         result = usb_control_msg (serial->dev, usb_sndctrlpipe (serial->dev, 0),
 855                                   BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
 856                                   0, NULL, 0, 100);
 857         if (result != 0)
 858                 dbg("%s(): error sending break", __FUNCTION__);
 859  */
 860 }
 861
 862 static void oti6858_shutdown(struct usb_serial *serial)
 863 {
 864         struct oti6858_private *priv;
 865         int i;
 866
 867         dbg("%s()", __FUNCTION__);
 868
 869         for (i = 0; i < serial->num_ports; ++i) {
 870                 priv = usb_get_serial_port_data(serial->port[i]);
 871                 if (priv) {
 872                         oti6858_buf_free(priv->buf);
 873                         kfree(priv);
 874                         usb_set_serial_port_data(serial->port[i], NULL);
 875                 }
 876         }
 877 }
 878
 879 static void oti6858_read_int_callback(struct urb *urb)
 880 {
 881         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 882         struct oti6858_private *priv = usb_get_serial_port_data(port);
 883         int transient = 0, can_recv = 0, resubmit = 1;
 884         int status = urb->status;
 885
 886         dbg("%s(port = %d, status = %d)",
 887                                 __FUNCTION__, port->number, status);
 888
 889         switch (status) {
 890         case 0:
 891                 /* success */
 892                 break;
 893         case -ECONNRESET:
 894         case -ENOENT:
 895         case -ESHUTDOWN:
 896                 /* this urb is terminated, clean up */
 897                 dbg("%s(): urb shutting down with status: %d",
 898                                         __FUNCTION__, status);
 899                 return;
 900         default:
 901                 dbg("%s(): nonzero urb status received: %d",
 902                                         __FUNCTION__, status);
 903                 break;
 904         }
 905
 906         if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
 907                 struct oti6858_control_pkt *xs = urb->transfer_buffer;
 908                 unsigned long flags;
 909
 910                 spin_lock_irqsave(&priv->lock, flags);
 911
 912                 if (!priv->transient) {
 913                         if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
 914                                 if (xs->rx_bytes_avail == 0) {
 915                                         priv->transient = 4;
 916                                         priv->setup_done = 0;
 917                                         resubmit = 0;
 918                                         dbg("%s(): scheduling setup_line()",
 919                                             __FUNCTION__);
 920                                         schedule_delayed_work(&priv->delayed_setup_work, 0);
 921                                 }
 922                         }
 923                 } else {
 924                         if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
 925                                 priv->transient = 0;
 926                         } else if (!priv->setup_done) {
 927                                 resubmit = 0;
 928                         } else if (--priv->transient == 0) {
 929                                 if (xs->rx_bytes_avail == 0) {
 930                                         priv->transient = 4;
 931                                         priv->setup_done = 0;
 932                                         resubmit = 0;
 933                                         dbg("%s(): scheduling setup_line()",
 934                                             __FUNCTION__);
 935                                         schedule_delayed_work(&priv->delayed_setup_work, 0);
 936                                 }
 937                         }
 938                 }
 939
 940                 if (!priv->transient) {
 941                         if (xs->pin_state != priv->status.pin_state)
 942                                 wake_up_interruptible(&priv->intr_wait);
 943                         memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
 944                 }
 945
 946                 if (!priv->transient && xs->rx_bytes_avail != 0) {
 947                         can_recv = xs->rx_bytes_avail;
 948                         priv->flags.read_urb_in_use = 1;
 949                 }
 950
 951                 transient = priv->transient;
 952                 spin_unlock_irqrestore(&priv->lock, flags);
 953         }
 954
 955         if (can_recv) {
 956                 int result;
 957
 958                 port->read_urb->dev = port->serial->dev;
 959                 result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
 960                 if (result != 0) {
 961                         priv->flags.read_urb_in_use = 0;
 962                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
 963                                         " error %d\n", __FUNCTION__, result);
 964                 } else {
 965                         resubmit = 0;
 966                 }
 967         } else if (!transient) {
 968                 unsigned long flags;
 969
 970                 spin_lock_irqsave(&priv->lock, flags);
 971                 if (priv->flags.write_urb_in_use == 0
 972                                 && oti6858_buf_data_avail(priv->buf) != 0) {
 973                         schedule_delayed_work(&priv->delayed_write_work,0);
 974                         resubmit = 0;
 975                 }
 976                 spin_unlock_irqrestore(&priv->lock, flags);
 977         }
 978
 979         if (resubmit) {
 980                 int result;
 981
 982 //              dbg("%s(): submitting interrupt urb", __FUNCTION__);
 983                 urb->dev = port->serial->dev;
 984                 result = usb_submit_urb(urb, GFP_ATOMIC);
 985                 if (result != 0) {
 986                         dev_err(&urb->dev->dev,
 987                                         "%s(): usb_submit_urb() failed with"
 988                                         " error %d\n", __FUNCTION__, result);
 989                 }
 990         }
 991 }
 992
 993 static void oti6858_read_bulk_callback(struct urb *urb)
 994 {
 995         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 996         struct oti6858_private *priv = usb_get_serial_port_data(port);
 997         struct tty_struct *tty;
 998         unsigned char *data = urb->transfer_buffer;
 999         unsigned long flags;
1000         int status = urb->status;
1001         int result;
1002
1003         dbg("%s(port = %d, status = %d)",
1004                                 __FUNCTION__, port->number, status);
1005
1006         spin_lock_irqsave(&priv->lock, flags);
1007         priv->flags.read_urb_in_use = 0;
1008         spin_unlock_irqrestore(&priv->lock, flags);
1009
1010         if (status != 0) {
1011                 if (!port->open_count) {
1012                         dbg("%s(): port is closed, exiting", __FUNCTION__);
1013                         return;
1014                 }
1015                 /*
1016                 if (status == -EPROTO) {
1017                         // PL2303 mysteriously fails with -EPROTO reschedule the read
1018                         dbg("%s - caught -EPROTO, resubmitting the urb", __FUNCTION__);
1019                         result = usb_submit_urb(urb, GFP_ATOMIC);
1020                         if (result)
1021                                 dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
1022                         return;
1023                 }
1024                 */
1025                 dbg("%s(): unable to handle the error, exiting", __FUNCTION__);
1026                 return;
1027         }
1028
1029         tty = port->tty;
1030         if (tty != NULL && urb->actual_length > 0) {
1031                 tty_insert_flip_string(tty, data, urb->actual_length);
1032                 tty_flip_buffer_push(tty);
1033         }
1034
1035         // schedule the interrupt urb if we are still open */
1036         if (port->open_count != 0) {
1037                 port->interrupt_in_urb->dev = port->serial->dev;
1038                 result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1039                 if (result != 0) {
1040                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1041                                         " error %d\n", __FUNCTION__, result);
1042                 }
1043         }
1044 }
1045
1046 static void oti6858_write_bulk_callback(struct urb *urb)
1047 {
1048         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
1049         struct oti6858_private *priv = usb_get_serial_port_data(port);
1050         int status = urb->status;
1051         int result;
1052
1053         dbg("%s(port = %d, status = %d)",
1054                                 __FUNCTION__, port->number, status);
1055
1056         switch (status) {
1057         case 0:
1058                 /* success */
1059                 break;
1060         case -ECONNRESET:
1061         case -ENOENT:
1062         case -ESHUTDOWN:
1063                 /* this urb is terminated, clean up */
1064                 dbg("%s(): urb shutting down with status: %d",
1065                                         __FUNCTION__, status);
1066                 priv->flags.write_urb_in_use = 0;
1067                 return;
1068         default:
1069                 /* error in the urb, so we have to resubmit it */
1070                 dbg("%s(): nonzero write bulk status received: %d",
1071                                         __FUNCTION__, status);
1072                 dbg("%s(): overflow in write", __FUNCTION__);
1073
1074                 port->write_urb->transfer_buffer_length = 1;
1075                 port->write_urb->dev = port->serial->dev;
1076                 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
1077                 if (result) {
1078                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1079                                         " error %d\n", __FUNCTION__, result);
1080                 } else {
1081                         return;
1082                 }
1083         }
1084
1085         priv->flags.write_urb_in_use = 0;
1086
1087         // schedule the interrupt urb if we are still open */
1088         port->interrupt_in_urb->dev = port->serial->dev;
1089         dbg("%s(): submitting interrupt urb", __FUNCTION__);
1090         result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1091         if (result != 0) {
1092                 dev_err(&port->dev, "%s(): failed submitting int urb,"
1093                                         " error %d\n", __FUNCTION__, result);
1094         }
1095 }
1096
1097
1098 /*
1099  * oti6858_buf_alloc
1100  *
1101  * Allocate a circular buffer and all associated memory.
1102  */
1103 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)
1104 {
1105         struct oti6858_buf *pb;
1106
1107         if (size == 0)
1108                 return NULL;
1109
1110         pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);
1111         if (pb == NULL)
1112                 return NULL;
1113
1114         pb->buf_buf = kmalloc(size, GFP_KERNEL);
1115         if (pb->buf_buf == NULL) {
1116                 kfree(pb);
1117                 return NULL;
1118         }
1119
1120         pb->buf_size = size;
1121         pb->buf_get = pb->buf_put = pb->buf_buf;
1122
1123         return pb;
1124 }
1125
1126 /*
1127  * oti6858_buf_free
1128  *
1129  * Free the buffer and all associated memory.
1130  */
1131 static void oti6858_buf_free(struct oti6858_buf *pb)
1132 {
1133         if (pb) {
1134                 kfree(pb->buf_buf);
1135                 kfree(pb);
1136         }
1137 }
1138
1139 /*
1140  * oti6858_buf_clear
1141  *
1142  * Clear out all data in the circular buffer.
1143  */
1144 static void oti6858_buf_clear(struct oti6858_buf *pb)
1145 {
1146         if (pb != NULL) {
1147                 /* equivalent to a get of all data available */
1148                 pb->buf_get = pb->buf_put;
1149         }
1150 }
1151
1152 /*
1153  * oti6858_buf_data_avail
1154  *
1155  * Return the number of bytes of data available in the circular
1156  * buffer.
1157  */
1158 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)
1159 {
1160         if (pb == NULL)
1161                 return 0;
1162         return ((pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size);
1163 }
1164
1165 /*
1166  * oti6858_buf_space_avail
1167  *
1168  * Return the number of bytes of space available in the circular
1169  * buffer.
1170  */
1171 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)
1172 {
1173         if (pb == NULL)
1174                 return 0;
1175         return ((pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size);
1176 }
1177
1178 /*
1179  * oti6858_buf_put
1180  *
1181  * Copy data data from a user buffer and put it into the circular buffer.
1182  * Restrict to the amount of space available.
1183  *
1184  * Return the number of bytes copied.
1185  */
1186 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
1187                                         unsigned int count)
1188 {
1189         unsigned int len;
1190
1191         if (pb == NULL)
1192                 return 0;
1193
1194         len  = oti6858_buf_space_avail(pb);
1195         if (count > len)
1196                 count = len;
1197
1198         if (count == 0)
1199                 return 0;
1200
1201         len = pb->buf_buf + pb->buf_size - pb->buf_put;
1202         if (count > len) {
1203                 memcpy(pb->buf_put, buf, len);
1204                 memcpy(pb->buf_buf, buf+len, count - len);
1205                 pb->buf_put = pb->buf_buf + count - len;
1206         } else {
1207                 memcpy(pb->buf_put, buf, count);
1208                 if (count < len)
1209                         pb->buf_put += count;
1210                 else /* count == len */
1211                         pb->buf_put = pb->buf_buf;
1212         }
1213
1214         return count;
1215 }
1216
1217 /*
1218  * oti6858_buf_get
1219  *
1220  * Get data from the circular buffer and copy to the given buffer.
1221  * Restrict to the amount of data available.
1222  *
1223  * Return the number of bytes copied.
1224  */
1225 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
1226                                         unsigned int count)
1227 {
1228         unsigned int len;
1229
1230         if (pb == NULL)
1231                 return 0;
1232
1233         len = oti6858_buf_data_avail(pb);
1234         if (count > len)
1235                 count = len;
1236
1237         if (count == 0)
1238                 return 0;
1239
1240         len = pb->buf_buf + pb->buf_size - pb->buf_get;
1241         if (count > len) {
1242                 memcpy(buf, pb->buf_get, len);
1243                 memcpy(buf+len, pb->buf_buf, count - len);
1244                 pb->buf_get = pb->buf_buf + count - len;
1245         } else {
1246                 memcpy(buf, pb->buf_get, count);
1247                 if (count < len)
1248                         pb->buf_get += count;
1249                 else /* count == len */
1250                         pb->buf_get = pb->buf_buf;
1251         }
1252
1253         return count;
1254 }
1255
1256 /* module description and (de)initialization */
1257
1258 static int __init oti6858_init(void)
1259 {
1260         int retval;
1261
1262         if ((retval = usb_serial_register(&oti6858_device)) == 0) {
1263                 if ((retval = usb_register(&oti6858_driver)) != 0)
1264                         usb_serial_deregister(&oti6858_device);
1265                 else
1266                         return 0;
1267         }
1268
1269         return retval;
1270 }
1271
1272 static void __exit oti6858_exit(void)
1273 {
1274         usb_deregister(&oti6858_driver);
1275         usb_serial_deregister(&oti6858_device);
1276 }
1277
1278 module_init(oti6858_init);
1279 module_exit(oti6858_exit);
1280
1281 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1282 MODULE_AUTHOR(OTI6858_AUTHOR);
1283 MODULE_VERSION(OTI6858_VERSION);
1284 MODULE_LICENSE("GPL");
1285
1286 module_param(debug, bool, S_IRUGO | S_IWUSR);
1287 MODULE_PARM_DESC(debug, "enable debug output");
1288